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The separate fields of conducting polymer-based electrochemical sensors and virus-based molecular recognition offer numerous advantages for biosensing. Grafting M13 bacteriophage into an array of poly (3,4-ethylenedioxythiophene) (PEDOT) nanowires generated hybrids of conducting polymers and viruses. The virus incorporation into the polymeric backbone of PEDOT occurs during electropolymerization via lithographically patterned nanowire electrodeposition. The resultant arrays of virus-PEDOT nanowires enable real-time, reagent-free electrochemical biosensing of analytes in physiologically relevant buffers.

Self-assembled monolayers (SAMs) of vinyl-terminated 3- and 8-carbon compounds were generated on Si substrates and reacted at room temperature with approximately 1 ppm gaseous O(3). A combination of atomic force microscopy (AFM), scanning electron microscopy (SEM), Auger electron spectroscopy (AES) and time-of-flight secondary ion mass spectrometry (TOF-SIMS) was used to study the surface composition and morphology after oxidation. A distribution of large ( approximately 0.1-10 microm) organic aggregates was formed, while the surrounding substrate became depleted of carbon compared to the unreacted SAM. This highly unusual result establishes that the mechanism of ozonolysis of alkene SAMs must have a channel that is unique compared to that in the gas phase or in solution, and may involve polymerization induced by the Criegee intermediate (CI). Oxidation at 60% RH led to the formation of a number of smaller aggregates, suggesting water intercepted the CI in competition with aggregate formation. The uptake of water, measured using transmission FTIR, was not increased upon oxidation of these films. In conjunction with literature reports of polymer formation from VOC-NO(x) photooxidations, these results suggest that formation of aggregates and polymers in the atmosphere is much more widespread than previously thought. The implications for the ozonolysis of alkenes on surfaces, for the transformation of organics in the atmosphere, and for the reactions and stability of unsaturated SAMs, are discussed.

This six-year study involved an evaluation of whether student-learning gains for an online homework system that emphasized areas in which students are known to have difficulties--molecular-level conceptualization and visualization, and being able to recognize and relate a concept when it is represented symbolically, numerically, or visually--could be sustained when scaled up to multiple sections and multiple instructors over several years. Thirteen sections of the same course were examined with 3,806 students taught by five different instructors. Results showed that the online homework led to higher achievement scores on final exams. Even when adjusted for students' level of preparation coming into the class, the online homework substantially influenced exam performance. Several mechanisms for the positive use of online homework by faculty and students, and issues of scaling up to the departmental level, are discussed. (Contains 4 tables and 2 figures.)

M13 virus particles were covalently attached to a planar gold-coated quartz crystal microbalance (QCM) through reaction with a self-assembled monolayer of N-hydroxysuccinimide thioctic ester, followed by incorporation of the blocking agent bovine serum albumin. This immobilization chemistry produced a phage multilayer having a coverage equivalent to [approximately equal to] 6.5 close-packed monolayers of the virus. The properties of this 'covalent virus surface' or CVS for the mass-based detection of a 148.2 kDa antibody were then evaluated in a phosphate buffer using a flow injection analysis system. The mass of the CVS increased with exposure to an antibody (p-Ab) known to bind the phage particles with high affinity. Bound p-Ab was removed by washing with 0.5 M HCI thereby regenerating the sensor surface. A calibration plot for p-Ab binding was constructed by repetitively exposing the surface to p-Ab at concentrations between 6.6 and 200 nM and HCl rinsing after each exposure. The mass--concentration relationship was linear with a sensitivity of 0.018 [micro]g/([cm.sup.2] nM) and a limit of detection of 7 nM or 1.3 pmol. The CVS could be saturated with high doses of p-Ab enabling the determination that an average of [approximately equal to] 140 binding sites are available per M13 phage particle. Exposure of the CVS to a second, nonbinding antibody (n-Ab) did not cause a measurable mass change. These results demonstrate that the covalent virus layer is a rugged, selective, and sensitive means for carrying out mass-based biodetection.

A dense virus layer, readily tailored for recognition of essentially any biomarker, was covalently attached to a gold electrode surface through a self-assembled monolayer. The resistance of this 'virus electrode', [Z.sub.Re], measured in the frequency range from 2 to 500 kHz in a salt-based pH 7.2 buffer, increased when the phage particles selectively bound either an antibody or prostate-specific membrane antigen (PSMA), a biomarker for prostate cancer. In contrast to prior results, we show the capacitive impedence of the virus electrode, [Z.sub.Im], is both a noisier and a less sensitive indicator of this binding compared to [Z.sub.Re]. The specificity of antibody and PSMA binding, and the absence of nonspecific binding to the virus electrode, was confirmed using quartz crystal microbalance gravimetry.

Noncontact atomic force microscopy was used to record observations of the (1->3)-beta-D-glucan linear triple helix to macrocycle interconversion. Results show that the native polymer dissolves in water as stiff and stable triple-stranded helices. Different structures are formed when the polymer is returned to temperatures favoring the formation of the triple helix. Findings are interpreted qualitatively based on a model for the renatured material.

Single-molecule fluorescence microscopy has provided information about the real-time distribution of chemical reactivity on silicon oxide supports at the solution-surface interface. Chemical reactions on the surface are uncorrelated, that is, the chemical reaction of one metal complex did not influence the location of a future chemical reaction of another metal complex.

Studies of the oxidation of the three-carbon and eight-carbon vinyl-terminated self-assembled monolayers on a silicon attenuated total reflectance (ATR) crystal by gas-phase ozone at 296K are reported. Possible mechanisms of the ozonolysis and its atmospheric implications are discussed.

A novel biomimetic modular polymer design is reported to address the challenge in polymer science to design polymers that combine desired mechanical properties such as tensile strength, fracture toughness, and elasticity into one structure. The excellent correlation between the single-molecule and the bulk properties successfully demonstrates biomimetic concept of suing modular domain structure to achieve advanced polymer properties.

Presents a study on (1...3)-beta-glucans. Identification of the glucans; Interest in the glucans for their immunostimulatory activity; Distribution of polymers of the glucans in plants, fungi, bacteria and yeast; Information on the linear backbone of schizophyllan and scleroglucan; In-depth look at the study; Methodology and results of the study.